천문우주과학과

일시:  2022년 5월 19일 목요일 오후 4시 세미나실(자4514호)

연사:  김홍서 박사님(한국천문연구원)

제목:  Central Engine Models for AGN(what is true nature Robbery or Delivery?) 

초록:  

For quite a long time, the consensus among the theoretical relativistic astrophysics community has been the long-standing idea of Blandford & Znajek [MNRAS 1976]. According to which, first, spinning supermassive black hole (BH), poloidal magnetic fields, and ‘force – free’ plasma work together under the principle set by the “Damour’s theorem”. In the meantime, in the context of ‘classical field theory’ in the background of the spinning supermassive BH, if one carries out the Thought Experiment where a Maxwell field(photon), as a ‘messenger’ is traversing. After being scattered off, the ‘messenger’ photon emerges with the greater frequency but with the same amplitude. which is exactly the process being referred to be the super radiant scattering (Super Radiance).

What is impressive is that this super radiant scattering of photons off the spinning supermassive BH upon being transported and observed by a distant observer. Which may well be identified with L ~ 10^ 46 (erg/ sec) of bright galaxies. Therefore, the above two alternative or competing models Could equally be relevant candidates for the central engine model for AGN.